Three New Species of Vernonia (Compositae: Vernonieae) from Mexico

Three new Mexican species ofVernonia,V. macphersonii,V. pugana andV. tequilana, are described.     

New species of Pectis (Asteraceae) from the West Indies,Mexico, and South America

Four new species ofPectis are described:P. ericifolia from Barbuda,P. luckoviae from west-central Mexico,P. arida from Ecuador and Peru, andP. cajamarcana from Peru. Chromosome counts forP. ericifolia (n=48) andP. luckoviae (n=12) are presented. Relationships of the newly described taxa are discussed.     

New taxa of Malpighia (Malpighiaceae) from Mexico and the West Indies

Malpighia romeroana var.nayaritensis is described from Nayarit, México, andM. albiflora subsp.antillana andM. nummulariifolia subsp.oblongifolia from the West Indies.     

Townsendia gypsophila (Compositae: Astereae): a new species from northern New Mexico

Townsendia gypsophila, a new species from Sandoval Co., New Mexico, is described and illustrated. It is a narrowly distributed obligate gypsophile closely related toT. fendleri andT. incana. It overlaps the ranges of the two taxa at the edge of their distributional limits in New Mexico.     

New host and locality records of coccidia (Apicomplexa: Eimeriidae) from rodents in the southwestern and western United States.

One hundred forty-seven murid and heteromyid rodents were collected from various sites in the southwestern and western United States (Arizona, Colorado, New Mexico, Texas, and Utah) and Baja California Norte, Mexico, and their feces were examined for coccidial parasites. Of these, 53 (36%) were infected with at least 1 coccidian; 45 of 53 (85%) of the infected rodents harbored only 1 species of coccidian. Infected rodents included: 10 of 22 (45%) Neotoma albigula, 3 of 11 (27%) Neotoma floridana, 2 of 14 (14%) Neotoma lepida, 15 of 29 (52%) Neotoma micropus, 5 of 8 (63%) Peromyscus crinitis, 6 of 6 (100%) Peromyscus difficilis, 1 of 2 (50%) Peromyscus eremicus, 9 of 34 (26%) Sigmodon hispidis, and 2 of 3 (67%) Sigmodon ochrognathus; 4 Neotoma cinerea, 3 Neotoma devia, 3 Neotoma mexicana, 1 Peromyscus maniculatus, 1 Onychomys leucogaster, 1 Onychomys torridus, 3 Chaetodipus fallax, and 2 Chaetodipus penicillatus were negative. Although no new species was found, the following coccidians were identified from infected rodents: Eimeria albigulae from N. albigula, N. floridana, and N. micropus, Eimeria antonellii from N. albigula and N. micropus, Eimeria ladronensis from N. albigula, N. floridana, N. lepida, and N. micropus, Eimeria arizonensis and Eimeria lachrymalis from P. crinitis and P. difficilis, Eimeria lachrymalis from P. eremicus, Eimeria tuskeegensis from S. ochrognathus, and Eimeria roperi, Eimeria sigmodontis, Eimeria tuskeegensis, Eimeria webbae, and an unidentified species of Eimeria from S. hispidis. This report documents 12 new host and several distributional records for Eimeria species from murid rodents in Arizona, Texas, and Utah.     

Range expansion of heterotheca camporum (Compositae: Astereae) in the Southeastern United States

Field and herbarium collection studies were used to document the relatively recent range expansion ofHeterotheca camporum (Greene) Shinners in the southeastern United States. Prior to 1925 the species was collected only in the Mississippi River valley of Missouri and Illinois and along the Wabash River in Indiana. By 1949 a “weedy” ecotype of the species had colonized parts of Kentucky, Tennessee and Alabama. Post-1950 collections indicate that it had spread through much of eastern Tennessee and reached Mississippi, Virginia and North Carolina. Typical plants may have expanded their range slightly in Indiana and southern Missouri since 1925. Populations from throughout the present range were found to be tetraploid, 2n=36. A morphometric study of herbarium collections and cytovouchers indicated that the “weedy” ecotype is distinguishable from most plants native to the pre-1925 range of distribution. In general the eastern morphotype is taller and more densely glandular than plants from the western part of the range. A new varietal name is proposed:Heterotheca camporum var.glandulissimum Semple.     

Philactis fayi (Compositae) : A new species from Mexico

The new species is the fourth member of the genus. Morphologically, it is most closely allied toP. liebmannii, but there are ample qualitative and quantitative differences between them. The chromosome numbers ofP. liebmannii andP. nelsonii are 2n = 56 whileP. zinnioides is 2n = 84.Philactis fayi is 2n = 28 and is considered to represent the diploid complement that was probably involved in the production of the other species through hybridization and chromosome doubling.     

Nitrogen loss from deserts in the southwestern United States

A lower limit for nitrogen loss from desert ecosystems in the southwestern United States was estimated by comparing nitrogen inputs to the amount of nitrogen stored in desert soils and vegetation. Atmospheric input of nitrogen for the last 10 000 years was conservatively estimated to be 2.99 kg N/m². The amount of nitrogen stored in desert soils was calculated to be 0.604 kg N/m³ using extant data from 212 profiles located in Arizona, California, Nevada, and Utah. The average amount of nitrogen stored in desert vegetation is approximately 0.036 kg N/m².Desert conditions have existed in the southwestern United States throughout the last 10 000 years. Under such conditions, vertical leaching of nitrogen below a depth of 1 m is small (ca. 0.028 kg N/m² over 10 000 years) and streamflow losses of nitrogen from the desert landscape are negligible. Thus, the discrepancy found between nitrogen input and storage represents the amount of nitrogen lost to the atmosphere during the last 10 000 years. Loss of nitrogen to the atmosphere was calculated to be 2.32 kg N/m², which is 77% of the atmospheric inputs.Processes resulting in nitrogen loss to the atmosphere from desert ecosystems include wind erosion, ammonia volatilization, nitrification, and denitrification. Our analysis cannot assess the relative importance of these processes, but each is worthy of future research efforts.     

Metastevia (Compositae: Eupatorieae): A new genus from Mexico

A new genus and species from Mexico,Metastevia hintonii, is described. The genus, considered to be closely related to and derived fromStevia, differs in seven morphological features from all known species ofStevia. The reasons for recognizing the new genus are discussed in detail.     

New taxa of Asteraceae from southern Mexico

Fieldwork in connection with the project to document the flora of the Mixteca Alta region, northwestern Oaxaca, Mexico, has resulted in the discovery of the following taxa: Verbesina calzadae and Viguiera grammatoglossa var. huajuapana (Heliantheae); Sinclairia manriquei (Liabeae); and Psacalium schillingii (Senecioneae).     

Coccidia (Apicomplexa) from heteromyid rodents in the southwestern United States, Baja California, and northern Mexico with three new species from Chaetodipus hispidus

Fecal samples from 223 heteromyid rodents of 4 genera and 13 species were collected from California, New Mexico, and Texas and from Baja California Norte and Sonora, Mexico. Of these, 84 (38%) were infected with coccidian oocysts; 72 of 84 (86%) infected animals had only 1 species of coccidian. Eleven species of coccidia were identified including 1 cyclosporan and 10 eimerians; the cyclosporan and 2 of the eimerians are described as new species. Sporulated oocysts of Cyclospora angimurinensis n. sp. were subspheroidal, 21.9 x 19.3 (19-24 x 16-22) microns, with sporocysts lemon-shaped, 11.9 x 9.5 (9-15 x 8-11) microns; it was found in 1 of 20 (4%) Chaetodipus hispidus. Sporulated oocysts of Eimeria chaetodipi n. sp. were subspheroidal, 16.7 x 14.6 (13-19.5 x 12-17) microns, with sporocysts ovoidal, 8.7 x 6.6 (7.5-10.5 x 5-7.5) microns; it was found in 3 of 20 (15%) C. hispidus. Sporulated oocysts of Eimeria hispidensis n. sp. were subspheroidal, 20.5 x 17.4 (17-23 x 14-21) microns, with sporocysts lemon-shaped, 9.3 x 7.2 (7.5-10.5 x 5-9) microns; it was found in 4 of 20 (20%) C. hispidus.(ABSTRACT TRUNCATED AT 250 WORDS)     

A new species of Polymnia (Compositae: Heliantheae) from Mexico

Polymnia mcvaughii from Jalisco, Mexico, is described as new. This herbaceous species appears to belong in the mainstream of evolution within the genus. It exhibits marked affinities to several species, but most closely resemblesP. oaxacana Schultz-Bip. Illustrations of important features are included, along with a list of key characteristics.     

A new species of Psilostrophe (Compositae) from Mexico

Psilostrophe mexicana is described as new and compared with the closely related speciesP. gnaphalodes. Chromosome numbers forP. mexicana are reported asn = 32, a tetraploid number. This new species is the seventh and only polyploid species in the genus.     

A new species of Bidens (Compositae) from Mexico

Bidens longistyla, an annual species with a square stem and yellow rays, known only from the States of Nuevo León and Coahuila, Mexico, is described as new.     

A new species of coreopsis (Compositae) from Mexico

Coreopsis mcvaughii, a small fruticose species known only from the State of Aguascalientes, Mexico, is described as new. It is assigned to sect.Pseudo-Agarista.     

Chromosome studies of cheilanthoid ferns (Pteridaceae: Cheilanthoideae) from the western United States and Mexico

Although analyses of chromosome numbers represent a fundamental step in the study of any group of organisms, the xeric-adapted cheilanthoid ferns (Pteridaceae: subfamily Cheilanthoideae) have received little attention from cytogeneticists due to the difficulty in obtaining samples and accurate chromosome counts. In an effort to clarify patterns of chromosomal evolution in this group, we present 131 chromosome counts representing 75 taxa of cheilanthoid ferns from the western United States and Mexico. First reports are provided for 24 taxa, including the first count for the genus Cheiloplecton. Nine other taxa yielded numbers that had not been reported previously. Our data suggest that chromosome base numbers are more stable than previously thought and that much of the reported variation may involve erroneous counts. When coupled with published DNA sequence data, our counts suggest that the plesiomorphic base number of subfamily Cheilanthoideae is x = 30 and that x = 29 has arisen just once or twice among the taxa studied.